Vacuum distillation



R. E. WILSON VACUUM DISTILLATION April 25, 1933.

Filed Jan. 2, 1930 L13 L18 Q2 fiober'i E 5071507 1 Patented Apr. 25, 1933 UNITED STATES PATENT OFFICE ROBERT E. WILSON, OF CHICAGO, ILLINOIS, ASSIGNOR TOSTANDARD OIL COMPANY OI CHICAGO, ILLINOIS, A CORPORATION OF INDIANA vacuum msrrmrron Application filed January 2. 1930. Serial No. 417,889.

This invention relates to a vacuum distillation process for petroleum oils and relates more particularly to a process for re fining heavy lubricating oils under hlgh vacuum.

The object of the invention is to provide a means for preventing excessive heat losses and for further minimizing entrainment in a vacuum still of the, type described in a co-pendin application b Payne and Miller, Serial 0. 417,585, filed ecember 30, 1929.

Other objects will be apparent as the detailed description of my invention proceeds. The invention contemplates the use of staggered bafiie plates spaced betweenthe heating element and the condensing surface of the still covered b the Payne and Miller application, the afiie plates being so designed that no droplet of heavy oil can be e ected from the evaporating column to the condensing surface. The baflle plates also serve to prevent heat transfer from evaporating surface to condenser surface in that they tend to reflect heat back to the evaporating surface and to radiate heat toward the evaporating surface.

My invention will be clearly understood from the description of the preferred embodiment which is illustrated in the accompanying drawing, wherein Figure 1 is a vertical section through my improved apparatus, Figure 2 is a section taken along the lines 22 of Figure 1, and

Figure 3 is a perspective of my improved bafile arrangement. I

I have shown my still enclosed in a tank having cylindrical sidewalls 10 and a top wall 11. A circular opening is provided in the top wall 11 which terminates in an annular flange 11A which supports the heating element and baflies as will be hereinafter described.

To the bottom wall 12 I secure a suction flask 13, divided into a condensate receiver 14 and a residue receiver 15 by concentric vertical walls 16 and 17 separated by suitable insulating material 18.

The usual side arm 19 of this flask is connected by a tube 20 to a suitable cooler wet vacuum pump.

' A cylinder 25 is mounted in cylinder tank 10 between top wall 11 and bottom wall 12, cylinder 25 being slightly larger in diameter than the opening in top 11. This arrangement provides a cooling tank 26 through which water or other cooling fluid may be circulated. This fluid is referably introduced through pipe 27 and opening 28 and is removed through openin 29 and pipe 30.

The outer baflle 31 is pre erably a metallic cylinder and is supported at its upper end 32' by flange 11A. The top 33 of cylinder 31 supports the heating element, as will be hereinafter described. The bottom of this baflie forms a funnel 34 for catching any entrained liquid which may have been deposited on the upper part of the cylinder.

The bafiie cylinder 31 may be described as an elongated cylinder having a series of horizontal slots or it may be described as a plurality of horizontal rings 35 separated and held in position by vertical posts 36.

Inside of this bafilc cylinder I provide a similar baffle cylinder 37 which is secured to the first named bafile by having its upper end 38 expanded against it. Baflle 37 is made in exactly the same way as baflie 31; it has horizontal slots or rings 40 spaced by posts 41. It is mounted so that the slots in the respective cylinders are in staggered relation, the slot of one baffle bemg entirely covered by the ring of the other baffle. By this means any'oil particle ejected from the evaporation surface is positively prevented from being projected against the condenser surface. 1

The evaporating surface is a vertical column 42. This may be an elongated tube provided with an electric heating element, 43, wrapped on insulating tube 44, and connected to suitable terminals 45 and 45. 0

An oil distributor 46 is mounted on the upper end of evaporator column 42, the 011 being supplied to the device through a conduit 47 in amounts regulated by valve 48.

The oil supply tank 49 is connected by a 20 and 50 to an absolute pressure below 50 mm. and the temperature of the evaporator column is brought to about 600 F. Water is circulated through the cooling chamber 26 and charging stock is admitted from tank 49 by properly adjusting valve 48. This charging stock may be a topped 'Mid-Continent crude, either before or after dewaxing. The oil moves by gravity down the heating column in a thin film and the lower boiling constituents are driven off as vapors, which are condensed on cylinder 25. The condensate runs down cylinder 25 to chamber 14 and is removed through pipe 22, while the residue drops from the heating column and baflies into funnel or on 34 which directs it into chamber 15, rom which it is removed by pipe 24.

Any particles of oil ejected from the heating column are caught by the baflle rings, and entrainment is therefore substantially eliminated. The most important feature of my invention, however, is the fact that these bafiie rings in the position indicated serve to insulate the condenser surface from the heating column by reflecting and radiatin the heat back against the film of oil. polished surface will, of course, reflect more heat than a dull surface, and I therefore contemplate the use of highly polished surfaces on my batfle plate, heating surface, and condenser plate.

While I have described in detail a preferred embodiment of my invention, it is understood that I am not limited thereto except as defined by the following claims.

I claim:

1. In vacuum distillation apparatus, a substantially vertical evaporating surface, means for heating said evaporating surface, means for flowing oil in a thin film over said surface, a condenser surface mounted close to said evaporating surface and substantially parallel thereto, and means interposed between said evaporating surface and said condenser surface for preventing excessive heat losse to the condenser.

2. In vacuum distillation apparatus, wherein a condenser surface is mounted adjacent and substantially parallel to a substantially vertical evaporator surface, means for distributing oil in a film over said evaporator surface, and means including a plurality of-sfisaggered baflie plates for preventing entrainment and for preventing excessive heat transfer between said evaporator surface and said condenser surface.

3. In vacuum distillation apparatus, wherein a condenser surface is mounted adjacentandsubstantially parallel to a substantially vertical evaporator surface, means including a plurality of staggered baflie plates for preventing entrainment and for.

.carbon oils which comprises flowing it in a thin stream over a heated surface, condensing evaporated componentson an adjacent condenser surface, and reflecting and radiating heat toward said heated surface by baffle plates spaced between said heating column and said condenser.

6. In a vacuum distillation apparatus, a polished heating surface, a polished condenser surface adjacent thereto, polished staggered bafile plates between said heating surface and said condenser surface for preventing entrainment and excessive heat losses.

7 In an apparatus of the class described,

.a vertical cylindrical heater, a vertical cysurrounding 1 lindrical condenser surface said heater, means for cooling said condenser surface, a column of spaced annular rings between said heater and said condenser and a staggered column of similar rings between said first column of rings and said heater, the staggered rings acting as baflies to prevent entrained oil particles from being ejected from the heater to the condenser surface.

Signed this 6th day of December, 1929, at Chicago, Illinois.

ROBERT E. WILSON. 

